90 research outputs found
Complementarity of Resonant Scalar, Vector-Like Quark and Superpartner Searches in Elucidating New Phenomena
The elucidation of the nature of new phenomena requires a multi-pronged
approach to understand the essential physics that underlies it. As an example,
we study the simplified model containing a new scalar singlet accompanied by
vector-like quarks, as motivated by the recent diphoton excess at the LHC. To
be specific, we investigate three models with -doublet, vector-like
quarks with Yukawa couplings to a new scalar singlet and which also couple
off-diagonally to corresponding Standard Model fermions of the first or third
generation through the usual Higgs boson. We demonstrate that three classes of
searches can play important and complementary roles in constraining this model.
In particular, we find that missing energy searches designed for superparticle
production, supply superior sensitivity for vector-like quarks than the
dedicated new quark searches themselves.Comment: References added; small bug found in model and analysis
implementation, numerical results slightly modified, conclusions unchange
Comfort care needs of cancer family caregivers (FCG) in outpatient palliative care : [poster]
PosterReferences and poster presented at the 2021 Midwest Nursing Research Society Annual Research Conference, March 24-27, 2021 (virtual)
How low can SUSY go? Matching, monojets and compressed spectra
If supersymmetry (SUSY) has a compressed spectrum then the current mass
limits from the LHC can be drastically reduced. We consider a possible 'worst
case' scenario where the gluino and/or squarks are degenerate with the lightest
SUSY particle (LSP). The most sensitive searches for these compressed spectra
are via the final state LSPs recoiling against initial state radiation (ISR).
Therefore it is vital that the ISR is understood and possible uncertainties in
the predictions are evaluated. We use both MLM (with Pythia 6) and CKKW- L
(with Pythia 8) matching and vary matching scales and parton shower properties
to accurately determine the theoretical uncertainties in the kinematic
distributions. All current LHC SUSY and monojet analyses are employed and we
find the most constraining limits come from the CMS Razor and CMS monojet
searches. For a scenario of squarks degenerate with the LSP and decoupled
gluinos we find GeV. For gluinos degenerate with the LSP
and decoupled squarks, GeV. For equal mass squarks and
gluinos degenerate with the LSP, GeV.Comment: References added, version submitted to ep
Combined LHC/ILC analysis of a SUSY scenario with heavy sfermions
We discuss the potential of combined analyses at the Large Hadron Collider
and the planned International Linear Collider to explore low-energy
supersymmetry in a difficult region of the parameter space characterized by
masses of the scalar SUSY particles around 2 TeV. Precision analyses of cross
sections for light chargino production and forward--backward asymmetries of
decay leptons and hadrons at the ILC, together with mass information on chi^0_2
and squarks from the LHC, allow us to determine the underlying fundamental
gaugino/higgsino MSSM parameters and to constrain the masses of the heavy,
kinematically inaccessible sparticles. No assumptions on a specific
SUSY-breaking mechanism are imposed. For this analysis the complete spin
correlations between production and decay processes are taken into account.Comment: new figure added, updated to match the published versio
Physics at the e+ e- Linear Collider
A comprehensive review of physics at an e+e- Linear Collider in the energy
range of sqrt{s}=92 GeV--3 TeV is presented in view of recent and expected LHC
results, experiments from low energy as well as astroparticle physics.The
report focuses in particular on Higgs boson, Top quark and electroweak
precision physics, but also discusses several models of beyond the Standard
Model physics such as Supersymmetry, little Higgs models and extra gauge
bosons. The connection to cosmology has been analyzed as well.Comment: 179 pages, plots and references updated, version to be published at
EPJ
Probing natural SUSY from stop pair production at the LHC
We consider the natural supersymmetry scenario in the framework of the
R-parity conserving minimal supersymmetric standard model (called natural MSSM)
and examine the observability of stop pair production at the LHC. We first scan
the parameters of this scenario under various experimental constraints,
including the SM-like Higgs boson mass, the indirect limits from precision
electroweak data and B-decays. Then in the allowed parameter space we study the
stop pair production at the LHC followed by the stop decay into a top quark
plus a lightest neutralino or into a bottom quark plus a chargino. From
detailed Monte Carlo simulations of the signals and backgrounds, we find the
two decay modes are complementary to each other in probing the stop pair
production, and the LHC with TeV and 100 luminosity is
capable of discovering the stop predicted in natural MSSM up to 450 GeV. If no
excess events were observed at the LHC, the 95% C.L. exclusion limits of the
stop masses can reach around 537 GeV.Comment: 19 pages, 10 figures, version accepted by JHE
The CLIC Potential for New Physics
The Compact Linear Collider (CLIC) is a mature option for the future of high
energy physics. It combines the benefits of the clean environment of
colliders with operation at high centre-of-mass energies, allowing to probe
scales beyond the reach of the Large Hadron Collider (LHC) for many scenarios of new physics. This places the CLIC project at a privileged spot in between the precision and energy frontiers, with capabilities that will significantly extend knowledge on both fronts at the end of the LHC era. In this report we review and revisit the potential of CLIC to search, directly and indirectly, for physics beyond the Standard Model
ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider
This paper reviews and extends searches for the direct pair production of the
scalar supersymmetric partners of the top and bottom quarks in proton-proton
collisions collected by the ATLAS collaboration during the LHC Run 1. Most of
the analyses use 20 fb of collisions at a centre-of-mass energy of
= 8 TeV, although in some case an additional 4.7 fb of
collision data at = 7 TeV are used. New analyses are introduced to
improve the sensitivity to specific regions of the model parameter space. Since
no evidence of third-generation squarks is found, exclusion limits are derived
by combining several analyses and are presented in both a simplified model
framework, assuming simple decay chains, as well as within the context of more
elaborate phenomenological supersymmetric models.Comment: 53 pages plus author list + cover page (70 pages total), 24 figures,
10 tables, submitted to Eur. Phys. J., All figures including auxiliary
figures are available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2014-07
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